Roof Design
Aim:
TO Design the Roof with the given section for the required dimensions and also the roof is being tested for the draft analysis and also the heat disortion test and snow load condition.
Answer:
The Roof is the outer top part of the car which is made of sheet metal using stamping process
the components of the roof are
- Outer roof
- Front Roof Rail
- Bow roof 1
- Center roof rail
- bow roof 2 and
- Back roof rail
The Front roof rail and back roof rail are common for all the cars and the central roof rail and bow roof rails are added according to the lingth of the car. the number of bow roofs also decided according to the length of the car.
For this case it is considered to be Two bow roofs along with the central roof
As the length of the car is long it is considered as two bow roofs and the placements of the roofs are considered at the center of front roof and center roof and also the bow roof is considered next to the center roof to with stand the load.
the design is being attached with the attachment.
The draft analysis are made and the image is being attached with the attachment it is clear with the Imagea that all the draft angle are maintained above 7 Degree.
the moment of inertia formula also shown in the image
the Tabulation of Heat load Calculation and Snow load calculations are shown below and both values are in the Go range
Heat Dissortion:
| places | Rx | Ry | R | T | l | r2/t | W | Decision | ||
| fr1-Bow roof 1 | 7131.5 | 3280.7 | 4494.019 | 0.75 | 69 | 3.51709 | 0.498173 | 0.0759 | 1.411163 | Go |
| Br1-Cr | 3082 | 4142 | 3534.231 | 0.75 | 69 | 3.51709 | 0.308106 | 0.0759 | 1.221096 | Go |
| Cr-Br2 | 5237 | 4169 | 4642.367 | 0.75 | 90 | 3.51709 | 0.531605 | 0.099 | 1.467695 | Go |
| Cr-Tail roof | 2838 | 4168 | 3376.758 | 0.75 | 66 | 3.51709 | 0.281262 | 0.0726 | 1.190952 | Go |
Snow Load:
| Places | Ly | t | Y(Caps) | My | Lx | Alpha | S | Rx | Ry | (Rx*Ry) | Iy | Iy*t^2 | Qr | Decision |
| fr1-Bow roof 1 | 2033 | 0.75 | 384 | 633216 | 1079 | 0.737216 | 330 | 11493 | 1692 | 43461056.25 | 2882 | 1621.125 | 15.33230737 | Go |
| Br1-Cr | 2033 | 0.75 | 648 | 897480 | 1079 | 1.044883 | 357 | 11316 | 2618 | 48539089 | 2690 | 1513.125 | 8.356940325 | Go |
| Cr-Br2 | 2033 | 0.75 | 436 | 696292 | 1079 | 0.810652 | 378 | 5460 | 4137 | 23025602.25 | 2097 | 1179.563 | 16.71798243 | Go |
| Cr-Tail roof | 2033 | 0.75 | 432 | 691632 | 1079 | 0.805226 | 237 | 2879 | 7610 | 27504780.25 | 0 | 0 |